We have previously demonstrated that the vergence eye movements resulting from sudden changes in the binocular disparity of large random-dot patterns have almost machine-like consistency and a latency of <60 ms in monkeys and <80 ms in humans. All indications are that these responses result from the activation of disparity selective neurons which are known to be present in a number of regions of the visual cortex. Recent experiments on monkeys by investigators in England have shown that disparity-selective complex cells in striate cortex respond to disparity steps applied to dense anticorrelated patterns in which the two eyes see patterns of opposite contrast (each black dot seen by one eye is matched to a white dot in the other eye). In accordance with local filter models of complex cells the disparity tuning curves of these neurons were often inverted with such patterns. An important point is that such stimuli do not give rise to perceptions of depth. We now report that disparity steps applied to dense anticorrelated patterns (50% coverage) elicit vergence eye movements at short latency from both monkeys and humans, and these responses strongly resemble those elicited by normal correlated patterns except that they are in the opposite direction. Thus, these vergence eye movements are generated in the absence of perceived depth, indicating that they must derive their visual input from an early stage of cortical processing prior to the level at which depth percepts are elaborated. Disparity steps applied to low-density anticorrelated patterns (<1% coverage) generated vergence at much longer latencies and this was in the same direction as with normal correlated patterns. Further, two-alternative-forced-choice tests were used to show that human subjects perceived depth in these low-density patterns, consistent with the idea that the normallydirected longer-latency vergence responses generated by these patterns result from higher-level cortical processing.